U.S. equity markets opened higher this morning and maintained their upward momentum for essentially the whole day. Lacking any really bad news from Asia or Europe, U.S. markets shrugged off a weaker than expected ISM non-manufacturing PMI number (more coverage here) and focussed instead on a generally upbeat day in European markets. In Asia, China's PMI came in better than expected and Australia's central bank left its key interest rate unchanged. In Europe, eurozone non-manufacturing PMI came in slightly better than expected. After yesterday's worst session of the year so far, today's trading seems positively sprightly.

The U.S. dollar index fell 0.02% today, now at 79.536. The GSCI commodity index is down 0.8% at 673.87, with commodities prices mixed again today. WTI crude oil closed up 0.5% today, at $96.64 a barrel. Brent crude trades up 0.8% at $116.54 a barrel. Natural gas is up 2.7% today at about $3.40 per million BTUs. Gold settled down 0.2% today at $1,673.50 an ounce.

The unofficial closing bells put the DJIA up more than 98 points to 13,978.53 (0.71%), the NASDAQ rose more than 40 points (1.29%) to 3,171.59, and the S&P 500 rose 1.04% or nearly 16 points to 1,511.26.

Earnings reports since markets closed last night resulted in several price moves today, including these: Anadarko Petroleum Co. (NYSE: APC) is up 3.3% at $83.15; Baidu Inc. (NASDAQ: BIDU) is down 10.4% at $96.06; Edwards Lifesciences Corp. (NYSE: EW) is down 6.7% at $86.79; Yum! Brands Inc. (NYSE: YUM) is down 2.8% at $62.15 (more coverage here); AGCO Corp. (NYSE: AGCO) is up 2.1% at $53.62; Allergan Inc. (NYSE: AGN) is up 1.6% at $106.75; Archer Daniels Midland Co. (NYSE: ADM) is up 3.4% at $29.42 (more coverage here); ARM Holdings plc (NASDAQ: ARMH) is up 4.3% at $43.76 after posting a new 52-week high of $44.00 earlier today (more coverage here); BP plc (NYSE: BP) is up 1.5% at $44.26 (more coverage here); Eaton Corp. (NYSE: ETN) is up 5.1% at $59.45 after posting a new 52-week high of $60.45 earlier today; Estee Lauder Companies Inc. (NYSE: EL) is up 6.1% at $64.79; Sirius XM Radio Inc. (NASDAQ: SIRI) is down 0.5% at $3.15; and Kellogg Inc. (NYSE: K) is up 0.8% at $58.55 after posting a new 52-week high of $59.30 earlier today.

Dell Inc. (NASDAQ: DELL) is up 1.3% at $13.45. The PC maker has agreed to be taken private in a deal worth more than $24 billion. More coverage here.

Arch Coal Inc. (NYSE: ACI) is down 12.4% at $6.07. The coal miner badly missed estimates this morning and the outlook for the first half of this year is not encouraging. More coverage here.

Opexa Therapeutics Inc. (NASDAQ: OPXA) is up 162.8% at $3.18. The biopharma company has struck a deal with Germany's Merck related to Opexa's treatment for multiple sclerosis. More coverage here.

The McGraw-Hill Companies (NYSE: MHP) is down 11.5% at $44.52. The financial information firm continued to get battered today as the U.S. Department of Justice announced charges against its S&P ratings agency for failure properly to let investors know the value of subprime mortgage bonds back in 2008.

Stay tuned for Wednesday. We have also noted the following events on the schedule (all times Eastern):